1. Field of Technology
The field of technology is data processing, or, more specifically, methods, apparatuses, and products for adjusting storage capacity in a computing system.
2. Description of Related Art
The use of solid-state storage devices (e.g., flash memory) in computer systems and storage systems is increasing due to the performance of flash memory as compared to traditional disk storage devices (e.g., hard disk drives (HDDs)). Flash memory offers low-power consumption combined with fast, random (input/output) I/O accesses as compared to traditional disk storage technology. Until recently, flash memory was used primarily in embedded applications, but the use of flash memory has expanded to other applications including desktop and enterprise storage.
Embedded applications which use flash memory typically include custom operating systems and custom file systems which are designed around the advantages and limitations of flash memory. However, when using flash memory in different applications, such as in desktop and enterprise storage, these systems often have legacy operating systems and file systems which are designed and optimized for use with HDD storage technology. These legacy operating systems and file systems are not able to take full advantage of all of the characteristics of flash memory. Also, these legacy systems may reduce the effective life of flash memory if wear leveling and other techniques are not utilized to prevent frequent writes to the same flash memory locations.
Additionally, inefficiencies are often introduced when integrating host storage systems with storage devices such as flash memory. For example, host file systems typically need to maintain a mapping between a logical location of a data block, as within a file, and the physical address of that block on the storage device. However, since the physical location of a block may change due to garbage collection and other device-internal processes, flash memory storage devices also maintain a mapping between the block address as provided by the host and the actual physical address of the block.
Many storage systems utilize data deduplication to reduce the total amount of data stored. One of the simplest and fastest techniques is to deduplicate using a fixed block size. When all blocks are the same size, garbage collection, allocation, overwriting, and data integrity are all simplified. However, supporting compression in addition to deduplication increases the complexity of these tasks. For example, compressed blocks will typically have different sizes, making it more challenging to track the amount of used and free storage space.